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THE MANUFACTURE 
OF STEEL BALLS 

DEVELOPMENT OF MACHINES AND METHODS 

BY ROBERT H. GRANT 



MACHINERY’S REFERENCE BOOK NO. 116 
PUBLISHED BY MACHINERY, NEW YORK 


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MACHINERY’S REFERENCE BOOKS 

This book is one of a remarkably successful series of 25-cent Reference Books 
listed below. These books were originated by Machinery and comprise a complete 
working library of mechanical literature, each book covering one subject. The price 
of each book is 25 cents (one shilling) delivered anywhere in the world. 


CLASSIFIED LIST OF REFERENCE BOOKS 


GENERAL MACHINE SHOP PRACTICE 

No. 7. Lathe and Planer Tools. 

No. 10. Examples of Machine Shop Practice. 

No. 25. Deep Hole Drilling. 

No. ,32. Screw Thread Cutting. 

No. 48. Files and Filing. 

No. 50. Principles and Practice of Assembling 

Machine Tools, Part I. 

No. 51. Principles and Practice of Assembling 

Machine Tools, Part II. 

No. 57. Metal Spinning. 

No. 69. Machines, Tools and Methods of Auto¬ 
mobile Manufacture. 

No. 91. Operation of Machine Tools.—The Lathe, 
. Part I. 

No. 92. Operation of Machine Tools.—The Lathe, 
Part II. 

No. 93. Operation of Machine Tools. — Planer, 
Shaper, Blotter. 

No. 94. Operation of Machine Tools.—Drilling Ma¬ 
chines. 

No. 95. Operation of Machine Tools.—Boring Ma¬ 
chines. 

No. 96. Operation of Machine Tools.—Milling Ma¬ 
chines, Part I. 

No. 97. Operation of Machine Tools.—Milling Ma¬ 
chines, Part II. 

No. 98. Operation of Machine Tools.—Grinding 
Machines. 

No. 116. Manufacture of Steel Balls. 

No. 120. Arbors and Work Holding Devices. 

TOOLMAKING 

No. 21. Measuring Tools. 

No. 31. Screw Thread Tools and Gages. 

No. 64. Gage Making and Lapping. 

No. 107. Drop Forging Dies and Die Sinking. 

HARDENING AND TEMPERING 

No. 46. Hardening and Tempering. 

No. 63. Heat-treatment of Steel. 

JIGS AND FIXTURES 

No. 3. * Drill Jigs. 

No. 4. Milling Fixtures. 

No. 41. Jigs and Fixtures, Part I. 

No. 42. Jigs and Fixtures, Part II. 

No. 43. Jigs and Fixtures, Part III, 

PUNCH AND DIE WORK 

No. 6. Punch and Die Work. 

No. 13. Blanking Dies. 

No. 26. Modern Punch and Die Construction. 

AUTOMATIC SCREW MACHINE WORK 

No. 99. Operation of Brown & Sharpe Automatic 
Screw Machines. 

No. 100. Designing and Cutting Cams for the Au¬ 
tomatic Screw Machine. 


No. 101. Circular Forming and Cut-off Tools for 
Automatic Screw Machines. 

No. 102. External Cutting Tools for Automatic 
Screw Machines. 

No. 103. Internal Cutting Tools for Automatic 
Screw Machines. 

No. 104. Threading Operations on Automatic 
Screw Machines. 

No. 105. Knurling Operations on Automatic Screw 
Machines. 

No. 106. Cross Drilling, Burringaand Slotting Op¬ 
erations on Automatic Screw Machines. 

SHOP CALCULATIONS 

No. 18. Shop Arithmetic for the Machinist. 

No. 52. Advanced Shop Arithmetic for the Ma¬ 
chinist. 

No. 53. The Use of Logarithms—Complete Log¬ 
arithmic Tables. 

No. 64. Solution of Triangles, Part I. 

No. 55. Solution of Triangles, Part II. 

THEORETICAL MECHANICS 

No. 5. First Principles of Theoretical Mechanics. 
No. 19. Use of Formulas in Mechanics. 

GEARING 

No. 1. Worm Gearing. 

No. 15. Spur Gearing. 

No. 20. Spiral Gearing. 

No. 37. Bevel Gearing. 

GENERAL MACHINE DESIGN 

No. 9T Designing and Cutting Cams. 

No. 11. Bearings. 

No. 17. Strength of Cylinders. 

No. 22. Calculation of Elements of Machine De¬ 
sign. 

No. 24. Examples of Calculating Designs. 

No. 40. Flywheels. 

No. 56. Ball Bearings. 

No. 58. Helical and Elliptic Springs. 

No. 89. The Theory of Shrinkage and Forced Fits. 

MACHINE TOOL DESIGN 

No. 14. Details of Machine Tool Design. 

No. 16. Machine Tool Drives. 

No. 111. Lathe Bed Design. 

No. 112. Machine Stops, Trips and Locking De¬ 
vices. 

CRANE DESIGN 

No. 23. Theory of Crane Design. 

No. 47. Electric Overhead Cranes. 

No. 49. Girders for Electric Overhead Cranes. 

STEAM AND GAS ENGINES 

No. 65. Formulas and Constants for Gas Engine 
Design. 


SEE INSIDE BACK COVER FOR ADDITIONAL TITLES 


MACHINERY’S REFERENCE SERIES 

EACH NUMBER IS ONE UNIT IN A COMPLETE LIBRARY OF 
MACHINE DESIGN AND SHOP PRACTICE REVISED AND 
REPUBLISHED FROM MACHINERY 


NUMBER 116 


THE MANUFACTURE 
OF STEEL BALLS 

By Robert H. Grant 


CONTENTS 


Making the Ball Blanks - -- ..---3 

Rough Grinding, Hardening and Finish Grinding - - 21 

Inspecting, Gaging and Testing of Balls - - - - 39 


Copyright, 1914, The Industrial Press, Publishers of Machinery, 
140-148 Lafayette Street, New York City 








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©CI.A369441 

MAR 23 1914 





CHAPTER I 


MAKING THE BALL BLANKS 

A review of the history of ball-making would take us back, it is 
claimed, more than four thousand years. The Chinese., who seem to 
have made everything first, are supposed to have made balls at that 
early date. This claim, however, is founded on a mere assumption and 
not on historical fact. Modern ball-making dates back to about 1870. 
Bicycles were then used to some extent in England, but as the bicycle 
was first made with a plain bearing, it was very laborious to propel; 
later cone bearings were introduced, and while these made the bicycle 
easier to work, it never became very popular until balls were used in 
the bearings. The first balls were made by the English workmen in 
their own homes, as was the custom in those days, by a very primitive 
method. A bar of steel of the proper size was placed in a chuck in a 
foot-power lathe. Then a ball was formed on the end of the bar by 
means of a hand tool, the long handle of which was pressed against 
the shoulder. The balls were made only a few thousandths of an inch 
larger than the finished size. They were then hardened and ground. 
The grinding was done between two cast-iron plates about eighteen 
inches in diameter. These plates were provided with concentric cir¬ 
cular grooves, and the balls were placed in these grooves with oil and 
emery. The top plate was then revolved by hand; it was removed at 
intervals and the balls measured until found to be of the proper size. 
These balls were sold for 12 cents apiece. At the present time balls 
of the same size, and of a superior quality, can be purchased for 1/7 
cent. 

First Machines for Manufacturing Balls 

The Simonds Rolling Machine Co., of Fitchburg, Mass., was the first 
company in the United States to engage in the manufacture of balls. 
This company was manufacturing a machine for making rolled forg¬ 
ings, and as by means of this machine it was possible to roll a very 
accurate ball, it was decided to start the manufacturing of this prod¬ 
uct. In Fig. 1 is shown a 3-inch rolling machine of the type mentioned, 
the size (3-inch) indicating the width of the platens. These platens 
run in opposite directions, and are operated by racks in the back, 
which, in turn, are driven by pinions on the driving shaft. The driv¬ 
ing shaft extends to the rear of the machine where the driving gears 
are located. The length of the stroke is changed by the dogs A, which 
can be moved to different positions in a grooved plate, as shown. 
The rest B supports the stock while it is,being rolled. The platens 
make about one-hundred strokes per minute. 

In Fig. 2 is shown a die for rolling balls on the Simonds machine. 
This die is held in a shoe which is fastened to the platen. The 30- 
degree beveled face on the die is knurled so that when the work is 
rolled, it will not slide through the dies, but rotate properly. The 


4 


No. 116—MANUFACTURE OF STEEL BALLS 


knurling of the beveled face of the dies was one of the most impc:- 
tant of the patents obtained by the company in connection with this 
development. The “invention,” however, was incidental. During the 
early stage of the development of the machine, a workman had been 
trying to roll a certain piece, but the stock would keep sliding through 
the machine without rolling. The operator then lost patience and, 
determined to make the stock roll, took a cold chisel and roughed up 



the edges of the die, with the result that the die immediately pro¬ 
duced perfect forgings. <3n the next set of dies made, he used a 
coarse knurl on the edges of the die to facilitate the proper movement 
of the stock. This method of knurling was patented in connection 
with the die, and this patent was considered one of the strongest in 
connection with rolling processes of this kind. 










































































MAKING THE BALL BLANKS 


5 


The method of rolling balls, however, is very wasteful on account 
of the fact that the stock which revolves over the knurled part of 
the die is thrown away as scrap. For every ball that is made, a 
diamond-shaped piece, as shown in Fig. 3, of the same diameter as 
the stock, has to be made and thrown away. In the illustration re¬ 
ferred to, A is the stock, B is the ball being rolled, and C the diamond¬ 
shaped piece which is wasted. Hence, it will be understood that this 
method is very expensive when used for ball-making, although the 
rolling method of forging can be used to advantage on long articles 
where the waste is proportionately small. 

In rolling methods of this kind there is a decided tendency to 
“pipe” the stock on account of the difference between the speed at the 
largest diameter and that at the “centers” of the ball, where, as a 
matter of fact, the metal is simply crushed and does not roll. Fre¬ 
quently there will then be a hole or pipe right through the center of 
the ball which will show after the teats at the end have been ground 
off. As an example of the tendency to pipe, it may be mentioned that 



once in the writer’s experience some spindles 12 inches long and 
5/16 inch in diameter were rolled with pipes right through so that 
a string could be put through the center. For this and other reasons, 
although the Simonds machine was most interesting from a me¬ 
chanical point of view, it had comparatively little value commercially. 

Several other ball companies had no good blanking process, and, 
therefore, hired men who understood the rolling process from the 
Simonds Co. A number of machines were thus designed similar to 
the Simonds type. One of these had circular platens instead of 
straight ones, and was made with circular dies, one within the other. 
The die holders, of course, were running in opposite directions. This 
machine worked satisfactorily, but the dies were much more difficult 
to make on account of their circular shape, and also on account of the 
fact that the inner die was smaller than the outer. The company 
designing this machine did not have a good grinding process and the 
machine was, therefore, soon abandoned on account of discontinuing 
the manufacture of balls. 



















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No. 116—MANUFACTURE OF STEEL BALLS 


Another rolling machine constructed on the same principle was made 
with platens of circular form running horizontally instead of vertically. 
The dies were circular, but of the same diameter, and were placed on 
the platen near the outer periphery. There were four dies in all to 
take up the circumference. The platens were run in opposite direc¬ 
tions to each other. This machine was very rapid in its action and 
continuous in its operation, as the dies always ran in one direction 
and did not have to reverse. Another rolling machine was made 


Fig. 4. The Christensen Ball Rolling Machine—U. S. Patent No. 632,336 

with two small circular disks with the dies cut in the periphery. 
These disks were keyed to spindles which were geared together and 
were made to run in opposite directions. This machine worked satis¬ 
factorily on small balls, and is still used by some of the smaller hall 
manufacturing firms. 

A number of machines have been designed from time to time for 
the making of ball blanks; some of these have been rather ingenious, 
although many of them have not been successful. In Fig. 4 is shown 
































































MAKING THE BALL BLANKS 


7 


a machine invented by Mr. M. F. Christensen, of Cleveland, 0. The 
slugs or blanks H are fed in at the upper end of a cone-shaped device. 

I 

The cone F revolves, being driven from pulley K. The inner face of 
the casing G is provided with a spiral groove from top to bottom, the 
section of the groove being more and more that of a complete circle 
as it approaches the bottom of the cone. The blank, as it runs around 
the cone, is supposed to be gradually rounded as it approaches the 
bottom. The machine, however, never proved successful for several 
reasons. The distance that the slugs or blanks had to travel proved a 
disadvantage, because if the slugs were heated, they became cold before 
they had passed through the device and would not compress, but 
were simply split open; if the slugs were not heated, the grain of 
the material was so distorted or crystallized that the balls could not 
be used. Again, if the slugs did not roll, but commenced to slide, 
causing clogging, the machine would have to be entirely dismantled 
in order to locate the trouble. Hence, after long and extensive experi¬ 
ments, it was abandoned. 

Machines for Turning- Ball Blanks 

On account of the piping and burning of the steel and the difficulty 
of removing the teats from the balls, the manufacturers next took up 
the turning process for making ball blanks. The first successful ma¬ 
chine invented was designed by the writer and is shown in Fig. 5. This 
machine is an automatic ball turning machine with a regular draw¬ 
back collet and automatic feed for the stock. The special feature of 
the machine is the manner of forming the ball. There is no turret 
slide or feed mechanism, but simply a solid tailstock with a heavy 
faceplate having a cam cut in the face, as indicated in the views at 
B and C. This cam is driven from cone pulley E through gears H , J 
and E. On the tailstock a plate with three jaws D , F and G is fastened, 
each of these jaws holding a forming tool and being provided with a 
roller which fits into the cam groove in the faceplate. When the 
machine is in operation, each jaw with its forming tool comes forward 
and does its share of the work (as indicated at L, M and N ), and is 
then moved back to allow the next jaw to come into action. The last 
or third jaw cuts off the ball and rounds the end of the stock so that 
there will be a proper surface on which to start the cut for the next 
ball. Another form of turning machine was provided with a head 
similar to a regular plain automatic machine, having for toolholders 
rocker arms operated upon by a shaft at the rear of the machine. The 
shaft allows the arms to descend onto the stock to form the ball and 
then moves them back while the cutting-off tool performs its work. 

The latest machine for ball turning is the Hoffmann machine shown 
in Fig. 6. This machine has two heads exactly alike, one at each end 
of the bed, these heads having regular automatic screw machine spin¬ 
dles. The slide in the middle of the bed is made very heavy because 
of being double and carrying two sets of forming tools. Four balls 
are formed at a time. The first ball from the stock end is about one- 
half finished, the second one, three-fourths finished, and the third one, 


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No. 116—MANUFACTURE OF STEEL BALLS 



Fig. 5. Tlie Grant Automatic Ball Turning Machine—U. S. Patent No. 517,004 






































































































































































































































































MAKING THE BALL BLANKS 


9 


completed, while the fourth ball is held in the second spindle, which 
is revolving at exactly the same speed as the first. This allows the 
forming tool to round the end of the ball so that it will be an accurate 
sphere. The ball is then fed on through the second spindle and drops 
into a pan. On account of forming four balls at a time, a roller rest 



is used in the rear of the slide. This rest has two rollers made of 
hardened steel against which the stock revolves while the forming is 
being done. This allows the forming tool to form a perfect ball, as 
the stock cannot recede while the tools are at work. This is a feature 
of considerable value when balls are turned from tool-steel rods which 
it is impossible to fully anneal. 























































































































































































10 


No. 116—MANUFACTURE OF STEEL BALLS 


When turning balls by the method described, the stock wasted is 
greater than that which goes into the ball. The method is, therefore, 
used very little for balls over one-fourth inch in diameter, because the 
price of the steel becomes an important factor in the cost of manu¬ 
facture when larger sizes are made. Another disadvantage is that 
balls cut from the bar are not as strong as when made by other 
methods. The direction of the grains or fibers of the steel wire is 
lengthwise of the bar; therefore, when the ball is formed, these fibers 
are cut and exposed at the surface, making a ball which is inferior in 
strength after hardening to balls made by other methods. 

Pressing Balls 

About fifteen or twenty years ago, when the bicycle business was 
booming, the Cleveland Machine Screw Co., which was at that time 
one of the largest of the firms in the country manufacturing balls, was 
unable to make enough blanks by the turning process, so it developed 
a process of pressing the ball blanks. In Fig. 7 is shown a regular 
wire straightener and cutting-off machine by which a coil of wire was 
straightened and then cut into short lengths called “slugs.” This 
cutting-off must be very carefully done as otherwise the ball made 
from the slug will be of poor quality, because of the ends or ragged 
parts being pressed into the ball and forming a cold shut. This may 
fall out during the grinding or hardening operations, the ball then 
having a pitted appearance. The length of the slugs also must be 
exact, otherwise the blanks will be badly out of shape. If the slugs 
are not square on the ends when placed in the die, they will crowd to 
one side, a lopsided ball being the result. 

In Fig. 8 is shown a regular No. 2 Ferracute press with an automatic 
attachment for pressing balls. This attachment is entirely automatic 
in its action, the slugs being fed down from the hopper and then con¬ 
veyed by an arm to the die where the ball is pressed, after which the 
latter is ejected by the knock-out. At A is shown the hopper which 
holds the slugs, and at G , a fork which works the hopper up and down, 
keeping the slugs falling into the tube B. Fork G is operated through 
the lever D which is given a reciprocating motion by cam E. Lever D 
also moves a rack operating pinion C, which latter has an arm attached 
to it that carries the slug from the bottom of tube B to the dies in the 
press proper. The press is so timed that the slug is firmly held 
between the dies for a moment before the dies come together, thus 
giving the feeding arm time to pull away. While the pressing is being 
done, the arm receives another slug from tube B. This method of 
pressing is very cheap and very little material is wasted. On account 
of the press being of the regular open-front type, however, the blanks 
can be pressed only a small amount, because otherwise the machine 
will spring away from the work which is not heated. Hence when 
larger diameters are pressed, the balls are only approximately spherical, 
and a large quantity of stock is left for the dry grinders to remove. 
It has, therefore, not been found practicable to press balls by this 
method when they are larger than % inch in diameter. 


MAKING THE BALL BLANKS 


11 



Slugs for Pressing into Balls for Pressing Balls 

Fig. 9 shows a machine designed by Mr. M. Reid for stock A, which comes in straight bars, is fed into the 
cutting the slugs tapering at both ends, so that when press- machine by gravity. Cutters .B (shown also in Fig. 10), 
ing the ball no ragged edge can be pressed into it. The somewhat similar to pipe cutters, sever the stock and at the 






























12 


No. 116—MANUFACTURE OF STEEL BALLS 


same time taper the ends. The stock is then fed to dies C and D and 
the ball is formed as indicated by the various illustrations in Fig. 10. 
As this process is done with heated stock, a very good blank is pro¬ 
duced. The sharp edges usually formed when cutting off the stock, 
are done away with by this method, and only the central part of the 
ball has to be pressed up, as the tapered ends are simply rounded. 

The Manville Machine 

The latest and best designed machine for the manufacture of small 
ball blanks is made by the E. J. Manville Machine Co., Waterbury, 



Fig. 9. The Reid Machine for Making Slugs with Tapered Ends and 
Pressing Balls—TJ. S. Patent No. 801,267 


Conn. This machine has a coining-press type of frame, except that it 
is horizontal instead of vertical. All the work is done inside of the 
frame, so that a very accurate blank can be produced on account of 
the rigidity thus obtainable. Fig. 11 shows one of the smaller sizes 


































































































































































MAKING THE BALL BLANKS 


13 


of these machines. This size is used for making balls up to % inch 
in diameter. The stock which comes in coils is first passed through 
the straightening rolls B and then through tube C into the cutting-off 
die. Slide E has a cam which carries the cutting-off device or tool F. 
This cutting-off tool is flat and has spring fingers as indicated in Fig. 
12. These fingers overlap the groove at the end of the cut-off tool. 


•f 



Fig-. 10. Diagrammatical Views of the Various Stages of the 

Reid Process 


After the stock has been cut off, these fingers hold the slug in position 
on the cut-off tool until the cam in slide E carries the tool with the 
slug over to the center of the dies. Die G is stationary and die H is 
mounted in movable slide K, which is carried forward by the eccentric 
on shaft A. As soon as the slug has been clamped between the two 
dies, the cut-off F moves back and allows the dies G and H to come 
together. The dies have holes drilled through them and are counter- 























































































































































14 


No. lie—MANUFACTURE OF STEEL BALLS 


bored from the back to within one-half inch from the impression in 
the die. (See Fig. 12.) In these counterbored holes, knock-out pins 
are placed which are worked by levers on the under side of the machine, 
so that as soon as the dies draw apart these pins will knock out the 
ball, no matter which die holds it. 

The machine is very rapid in its operation and regular 3/16-inch 



Fig. 11. The E. J. Manville Machine Co.’s Rivet Header arranged 

for Making Balls 


balls can be made at the rate of 100,000 to 125,000 per day, according 
to the grade of the stock and the character of the annealing. One man 
can run three or four of these machines; hence the labor cost is so 
small as to be almost negligible. As there is no waste, this process, 
for smaller sizes of balls, must be deemed the best as well as the 
cheapest in ball manufacture at the present time. The following table 
gives sizes of stock used for making different sizes of balls: 


Diameter of 
Ball, Inch 

1/8 

5/32 

3/16 

7/32 

1/4 


Diameter of 
Stock, Inch 

0.095 

0.120 

0.145 

0.165 

0.180 


Diameter of 
Ball, Inch 

9/32 

5/16 

3/8 

7/16 

1/2 


Diameter of. 
Stock, Inch 

0.200 

0.225 

0.265 

0.312 

0.355 


Ball Forging 


The best known method of making ball blanks from % inch to 2 
inches in diameter is known as string forging. Fig. 13 shows a regular 







MAKING THE BALL BLANKS 


15 


upright helve hammer and a press, as well as a heating forge, the equip¬ 
ment being arranged for string forging. The bars from which the balls 
are forged are approximately 6 feet long. Twelve of these bars are put 
into the furnace at a time and are heated so that two sets of balls can 
be forged before putting the bar back into the furnace. By having a 
number of bars in the furnace at the same time, the heating can be done 
slowly and uniformly, and the bars are heated clear through to the 
center of the stock without burning or decarbonizing the surface. The 
forging of the balls requires some skill, as the bar must be turned and 
the hammer started at high speed, gradually slowing up as the blank 
begins to assume its proper shape. After being forged, the string of 
forged balls, indicated at A in Fig. 19, is placed in the trimming press 
where the whole row is forced through a series of holes, thus trimming 




_ fachtnery 

Fig. 12. Details of Cut-off Slide and Dies of Machine in Fig-. 11 

off the fins and separating the balls into individual blanks. The balls 
drop directly into a box under the press, as indicated. 

Fig. 14 shows by a number of diagrammatical illustrations the manner 
in which the dies for string forging are made. At A is shown a section 
of a die with four impressions. The illustration also gives the notation 
of the die details necessary for use in connection with the following 
table. At A, for example, is indicated the diameter D of the cutter or 
cherry used in sinking the die, and also the depth E to which the cutter 
is sunk. In the view at B is given the distance G between the centers, 
so selected that w r hen the proper size of stock is used, the die cavity 
will just be filled. It is also indicated here and at F that the die must 
be backed off or relieved on each side of the impressions, leaving only 
a small amount of land in the center to do the hammering. This back¬ 
ing off is done by moving the jig around on the milling machine or die 
sinking machine, and sinking the cutter or cherry into the die about 


































16 


No. 116—MANUFACTURE OF STEEL BALLS 





hi 

a ' i'U 

WM 

4 .. \ - slli" ’ 




i V-. W jL ... 


Fig. 13. Upright Helve Hammer and Press, arranged for String Forging of Balls 








MAKING THE BALL BLANKS 


17 


1/16 inch, leaving the width of the center about one-third of the diam¬ 
eter of the ball. At G is shown the depth of the bridge, which is very 
important, as the neck formed by the bridge must hold the balls together 
during the forging and not draw the stock near the neck, so as to cause 
a pipe, which is very easily done. At H is shown the size of the stock 



Machinery 

Fig. 14. Details of Dies for String Forging 

which is always smaller than the diameter to be forged. The stock must 
be close to the required size; otherwise difficulties will be met with. 
If under size, the balls will not fill out; if too large, extra hammering 



Fig. 15. Tools used for Trimming the Balls after Forging in a String 

will be required, which causes the dies to soon wear out. In Fig. 14, 
four balls are shown forged at a time, but as this illustration is only 
diagrammatical, it is not implied that this is the correct number used 
in practice. The following table gives the number of balls that would 























































































18 


No. 116—MANUFACTURE OF STEEL BALLS 


be forged in a string for different sizes of balls, together with other 
dimensions required for the sinking of dies. At K is shown the stock 
after it has been slightly hammered to see if the dies are in perfect 
alignment. It is easily seen that when there are so many impressions 
in the dies, if the die warps in the hardening, the two dies will not 
match perfectly, and the balls at either end may be rather poor in 
quality. It is, therefore, very important to use a die steel that will hold 
its shape after hardening. 


DATA FOR STRING FORGING OF BALLS 
(See Fig. 14 for Notation.) 

Distance 


Size of 

Size of 

Diam. of 

Between 

Depth of 

Depth of 

No. of 

Balls 

Stock, H 

Cutter, D 

Centers, C 

Cavity, E 

Bridge, G 

Balls 

3/8 

0.320 

0.395 

0.485 

0.198 

0.040 

18 

7/16 

0.375 

0.457 

0.550 

0.228 

0.050 

16 

1/2 

0.437 

0.520 

0.615 

0.260 

0.050 

14 

5/8 

33/64 

0.645 

0.755 

0.322 

0.060 

12 

3/4 

39/64 

0.775 

0.910 

0.387 

0.065 

9 

7/8 

23/32 

0.905 

1.060 

0.452 

0.065 

8 

1 

13/16 

1.035 

1.210 

0.517 

0.075 

7 


The necessary tools for the trimming of the balls are shown in Fig. 15. 
At A is shown the holder for the punches, the shank fitting into the 
head of the press. At B is shown a plate with holes drilled to the same 
diameter as the shanks of the punches. This plate is sawed in two, 
and after the punches are placed in the holes, it is clamped in holder A 
and held in place by four set-screws. The diameter F of the punches 
is about one-eighth inch less than the diameter of the balls. At C is 
shown a bolster fastened to the press and at D a plan of the die that is 
drilled with the same distance E between the centers of the holes as 
the distance between the forged balls. A groove is provided between 
the holes drilled in the bottom die D so that the necks between the 
balls will not touch the top of the die. Die D is placed in bolster G 
and lined up with the punches as in ordinary stamping processes. 

The furnace used for heating the stock is of a special oil burning 
type. The burner is placed on the side of the furnace midway between 
the front and the rear. By having a special form of baffle plate directly 
in front of the flame, the latter is distributed throughout the furnace 
before it comes out at the front. An air pipe is passed under the 
opening through which the stock is put in to be heated. This pipe 
has a number of small holes drilled in the side facing the opening, 
and when air is forced through these holes, the heat is diverted upward 
and kept away from the operator. 

Large balls, from 2y 2 inches up, are usually forged under a steam 
hammer. Stock of the proper diameter is first cut off to the required 
length and both ends are chamfered. The length of the stock is 
determined by the weight of the finished ball, an allowance for finish¬ 
ing being added. The blanks are placed in an oil furnace and allowed 
to heat slowly. Each time a blank is forged, a new one is put into 
its place in the furnace. The dies for this kind of forging are of an 
entirely different form from those used for string forgings. They are 


MAKING THE BALL BLANKS 


19 


cupped out to the desired diameter, but are only sunk to a depth of 
one-quarter of the diameter of the ball to be forged, and are not backed 
off. When the blank is heated, the hammer man places it in the die, 
and the hammer is worked very slowly until the ball begins to take 
a spherical shape, at which time quicker and heavier blows are struck. 
On account of the impressions in the dies being so shallow, the opera- 



Fig. 16. “Flasher” or Rotary File used for Removing Fins from 

Forged Balls 

tor has ample space to turn the ball in all directions, and can, there¬ 
fore, produce an almost true sphere. Blanks 4 inches in diameter have 
been forged that have not been out of round over 0.005 or 0.006 inch. 

The Flashing Process 

The ball blanks as they come from the press or hammer are more or 
less out of shape and have a flash or fin or some other projection 
caused by the cutting-off or the wearing of the dies. These fins must 
be removed before the first grinding as they would otherwise mar the 
grinding rings. In Fig. 16 is shown what is known as a rotary file or 
flasher used for removing these fins. The balls are fed through the 


I 

















20 


No. 116—MANUFACTURE OF STEEL BALLS 


spindle by gravity and discharged from the rotary filing plates by 
centrifugal action. The head of the machine, which is run by a worm 
and worm-wheel, has a spindle to the end of which the rotary file is 
attached. As the spindle is hollow, the balls can be fed through it to 
the center of the plate. The lower plate is solid, but is adjustable up 
and down, allowing for different sizes of balls and for wear. The balls 
as they pass from the spindle to the center of the plate, are filed by 
the upper plate revolving and forcing them over the lower, and they 



Fig-. 17. Principle of Multi- Fig. 18, Method of Flashing 

pie Ring Grinder Large Balls 


fall out at the outer edge into a basket. The operation is repeated 
after the lower plate has been adjusted. The plates are kept from 
clogging by a mixture of lard and kerosene oil, circulated by a pump 
from a tank below to a reservoir above. 

There is also another method of removing the flash or fin from the 



Fig. 19. Sample of Balls made by Various Processes at Different 

Stages of Completion 


balls, known as the multiple ring grinding process. Fig. 17 shows a 
diagrammatical sketch of the principle of this method. Rings which 
are slightly grooved are placed on a heavy grinder similar to a drill 
press. The grooves are filled with balls and No. 36 emery or carborun¬ 
dum. The top ring is fastened to the spindle and allowed to revolve 
at a high speed while pressure is being applied. In a short time the 
balls are removed and found to be comparatively smooth and ready 
for the first dry grinding. 


































GRINDING AND HARDENING 


21 


The. larger balls are ground separately in a very simple but effective 
way, as indicated in Fig. 18. An upright A is bolted to the table of a 
small emery wheel grinder. This upright has a tapered hole through 
it into which the ball is pushed and adjusted so that the ball after the 
flash has been removed will barely touch the emery wheel. The opera¬ 
tor, by means of a short pair of tongs, can turn the ball in all directions. 
As the ball cannot pass through the tapered hole in the upright more 
than a certain distance, flat spots cannot be ground, but the fin is 
simply removed and a smooth surface produced. 

In Fig. 19 are shown a number of samples of balls made by various 
processes and at different stages of completion. At A is shown a string 
of forged balls, and at B forged balls after trimming. At C are shown 
a number of balls after being rough ground, at D the end of a bar 
operated upon in a Hoffmann ball turning machine, and at E a number 
of slugs and balls pressed from them. 

Kind of Steel Used in Ball-making 1 

The most important thing to be considered in the manufacture of 
balls is the quality of steel used. One of the largest elevator com¬ 
panies in the United States tried 432 different samples of steel, ob¬ 
tained in this country and abroad. Balls from these samples were made 
and tested by being put into actual use. From these tests it was ascer¬ 
tained that the two grades of steel below (carbon and alloy) are best 
suited for making steel balls. 

1. —Carbon, 1.12; silicon, 0.015; phosphorus, 0.017; manganese, 0.19; 
sulphur, 0.019; chromium, 0.25 per cent. 

2. —Carbon, 0.95; silicon, 0.014; sulphur, 0.019; phosphorus, 0.018; 
manganese, 0.025; chromium, 1.25; tungsten, 0.25 per cent. 

It may be said without exaggeration that balls are used in nearly 
every kind of article that it is possible to name, provided it revolves. 
They are used in the cheapest kind of hardware and in the finest mech¬ 
anisms and surveyors’ instruments. Balls 1/16 inch in diameter are 
used in electric meters and typewriters. The number of balls being 
used for these purposes alone is from fifty to seventy-five millions per 
year. The largest balls made are about 6 inches in diameter. 


CHAPTER II 


ROUGH GRINDING, HARDENING AND 
FINISH GRINDING 

In the previous chapter, the methods of making the blanks and 
preparing them for the dry grinding were explained. In the present 
chapter the grinding and hardening operations will be dealt with. The 
old English method of grinding the balls was mentioned in the previous 
chapter, the balls being ground between two circular plates, the upper 
one of wjiich was revolved by hand. The increased demand for balls 


22 


No. 116—MANUFACTURE OF STEEL BALLS 


in the bicycle industry soon brought about improved methods for 
grinding, the first step being to fasten the top plate to the spindle of 
a drill press, while the bottom plate rested on the table of the machine. 
In this way work was produced very much faster, but no better quality 
was obtained than formerly. About the time when the first steel balls 
were manufactured in this country, special grinding heads of a much 
more substantial character were devised. Fig. 20 shows a row of oil 
grinders, such as were first made in this country. The head is made 
in the form of a goose neck, and has three bearings. The lower, or 
main, bearing has a quill the same as a drill press, with a rack cut in 
it. A lever with pinion teeth cut on the end meshes with this rack 
and provides the means for raising and lowering the head. The spindle, 
which has a large faceplate fastened to the lower end, carries the 



Fig. 20. Battery of Early Type of Ball Grinding Machines 

upper grinding ring, which is fastened to the faceplate by three screws. 
The main drive is through a set of bevel gears on the countershaft 
directly over the spindle of the machine. A vertical shaft transmits 
the power from the countershaft to the spindle. As all the blanks at 
this time were either pressed or forged, instead of being turned, the 
amount of stock to be removed was considerably more than it is when 
turned ball blanks are used. For this reason the time required for 
grinding ^4-inch balls was from one-half to three-quarters of an hour, 
and if the rings were badly worn the balls would come out of the 
grinder considerably out of true. It was, therefore, necessary to devise 
a better and quicker process—a rough grinder—for removing the sur¬ 
face of the balls., It is especially necessary to remove the surface to 
some depth when the balls are forged, as the outside is then apt to be 
decarbonized. 







GRINDING AND HARDENING 


23 


The Richardson Rough Grinder 

The first rough grinder for halls was made by Mr. Henry Richardson, 
president of the Waltham Emery Wheel Co., Watham, Mass., in 1877. 
Mr. Richardson, in speaking of this machine, has mentioned a few 
interesting facts about his experiments along this line. He took a 
regular 16-inch bastard file and ground a 90-degree groove in the 
center, almost the entire length of the file. The groove was ground 

clear through the file 
so that it would allow 
a 5/16-inch ball to pro* 
ject through to such an 
extent that the ball 
could be ground by a 
wheel without the lat¬ 
ter touching the file. 
An emery wheel was 
then fastened to the 
faceplate of a lathe, and 
the file was clamped to 
the carriage in a verti¬ 
cal position. A plate 
with an elongated slot, 
which could be moved 
up and down on the 
tailstock spindle, was 
then made. The file 
with the balls was now 
Pi a c e d against the 
balls. The lathe was 
then started. The balls 
at once began to move 
in the V-groove in the 
file, and by moving the 
plate on the tailstock 
spindle up and down, 
the balls were turned 
in all directions, pro¬ 
ducing in a very short 
time a blank which was 
a comparatively true sphere, fairly accurate as to dimensions. 

Mr. Richardson then made a trial machine which worked very satis¬ 
factorily, but as a photograph of this machine was never made, no 
record of its appearance is preserved. In 1878 he went to England and 
sold the English patents to Mr. Wm. Sown. A sample machine, as 
shown in Fig. 21, was made at this time. The patent held by Mr. 
Richardson did not, however, properly cover the invention, so that he 
was unable to get full returns for his efforts. The only claim of any 
importance which he held was as follows: a ring of balls in a Y-groove, 



Fig. 21. Richardson’s Ball Grinder 










24 No. 116—MANUFACTURE OF STEEL BALLS 

revolved by a driving ring and exposed to an emery wheel. This claim 
was the direct result of his experiments, and by itself was very far- 
reaching. It gave the ball makers, who soon began to spring up all 
over the country, a great deal of trouble in their efforts to “go 
around” it. 



Fig. 22. Diagrammatical View of Principal Arrangement in tlie 
Richardson Ball Grinder 


As shown in Fig. 21, the emery w r heel is placed on the lower spindle 
which is mounted in the movable head; this head is operated by the 
handwheels at the rear of the machine. The emery wheel is eccentric 

r- 


mm 


fL_n 

Machinery 

Fig. 23. Principle of the John J. Grant Rough Grinder—IT. S. Patent 

No. 535,794 

with the top ring, so that the whole surface of the wheel will succes¬ 
sively come in contact with the balls. This keeps the wheel in perfect 
shape. The V-groove in which the balls rest is formed by two annular 













































































GRINDING AND HARDENING 


25 


rings or plates (see diagrammatical view in Fig. 22); the outer one is 
held and adjusted by three long bolts (shown in Fig. 21), while the 
inner plate is fastened to a rod which passes through the drive shaft 
to the top of the machine. This inner plate is operated by the middle 
lever shown, so that the balls thus can be “dropped” when finished. 
The driving ring which revolves the balls is adjustable in an up and 
down direction by means of the lower lever, and is clamped in the 
proper position by the small lever on the main bearing. This driving 
ring runs in the opposite direction to the emery wheel; the latter is 
run at a peripheral speed of approximately 5000 feet a minute. 

On account of the fact that the outside of the balls run faster than 
the inside, as they are driven around by the drive ring, the balls 
assume a spiral motion, thereby exposing all sides to the emery wheel. 
An approximately accurate sphere is thus produced. 

The John J. Grant Rough Grinder 

In 1888 when the Simonds Rolling Machine Co., of Fitchburg, Mass., 
was grinding balls by the old English method, it could only produce 
balls which were true within 0.003 inch. This accuracy was considered 
sufficient at that time. Mr. John J. Grant, who was at that time 
employed by this company, and who had improved the Simonds rolling 
machine, proceeded to devise a machine which made it possible to 
produce balls far superior to any ever made. The principle of his first 
machine, which was a rough grinder, is shown in Fig. 23. This machine 
produced excellent work, but was very slow in its operation, as the 
balls had to travel one-half of the circumference of the groove in the 
ring without coming in contact with the emery wheel. On balls of 
smaller sizes, the upper or driving ring was so thin that it was possible 
to grind but a few balls before the emery wheel would wear it away. 
As shown in Fig. 23, the balls were held at the periphery of the sta- 
tionary ring in a V-groove. The drive ring was extended over the 
balls far enough to drive them, and was driven ,by a pulley on the 
spindle which held the drive ring. The speed was not over 60 revolu¬ 
tions per minute. A saddle, which was stationary on the base of the 
machine, carried the emery wheel heads, each head having two wheels, 
so that the surface coming in contact with the ball would be as wide 
as possible. The driving pulley was placed between the emery wheels, 
all being driven from the same countershaft. The upper or drive ring 
could be raised by a lever at the top of the machine, and the lower ring 
could be revolved by throwing out a latch with a foot lever. This 
allowed the machine to be loaded and unloaded very rapidly. Not¬ 
withstanding the fact that this machine was very slow, as compared 
with the Richardson machine in which the emery wheel was on the 
balls at all times, it was successful, and it was possible for the Simonds 
company to produce a ball better than those produced by any other 
manufacturers, and the company soon controlled the ball trade. 

In 1891, the Grant Anti-Friction Ball Co., was formed by Mr. J. J. 
Grant, and a great many experiments in the dry grinding of balls 
without the V-path and drive ring were undertaken, but the experi- 


26 


No. 116—MANUFACTURE OF STEEL BALLS 



ftg. 24. Robert H. Grant Dry Grinding Machine—IT. S. Patent No. 520,019 





































































































































































































































































































































GRINDING AND HARDENING 


27 


merits were not successful. It was, therefore, necessary to buy Mr. 
Richardson s patent, and around this was built the most successful dry 
grinder ever produced. 


The Robert H. Grant Dry Grinder 

In Fig. 24 are shown general and sectional views of the R. H. Grant 
grinding machine, as originally made. It will be seen that the Richard¬ 
son path is used in a modified form. The drive ring is driven through 
a gear on the drive ring holder, this gear, in turn, being driven by 
pinion U which is fastened to the shaft A. This shaft carries pulley G 
at its upper end. The cone B has a plate with hardened segments 
screwed to its lower end which form the inner part of the race N. The 
cone is fastened to the shaft D which is adjustable by collar E. On 
the upper end of the shaft is a spring F which is compressed between 
the collar 1 and the adjustable sleeve G. By means of the lever H, the 
shaft D can be lowered, thereby allowing the balls to drop into a 
receptacle after being ground, as shown in the view to the right. On 



the rear of the quill J, which carries the shaft D, is cut a rack in 
which pinion R works. The shaft T which operates pinion R is ad¬ 
justed by the spring P, controlled by the handwheel 8. On the lower 
part of the quill J is fastened the spider 0 which carries the ring M, to 
which are screwed the hardened segments forming the outer path. 

It will be seen that when the rough forgings are placed in the V-path, 
the driving ring is stationary, but the inner ring can vibrate on 
account of the action of the spring F. The outer ring M is permitted 
to vibrate slightly through the means of the spider 0. quill J, pinion R 
and spring P. In this way the rough forgings will be ground only on 
the high spots until the balls become round. 

The loading and unloading is done without stopping. When the 
balls are finished, the emery wheel is lowered and a pan is pushed 
under the path of the balls. The handle Ft is pulled down, thus allow¬ 
ing the balls to fall into the pan. The spider 0 is then lowered by 



















28 


No. 116—MANUFACTURE OF STEEL BALLS 



Fig. 26. The Putnam Dry Grinder—U. S. Patent No. 664,823 Fig. 27. Details of Principal Parts of the Putnam Grinding Machine 



































































































































GRINDING AND HARDENING 


29 


means of the lever on the end of the shaft carrying pinion R. This 
allows the balls to be ground to be fed into the path N, and permits 
the grinding to commence without interruption. 

The emery wheel, which is eccentric with the path of the balls, so 
as to allow the balls to successively cover the whole surface of the 
wheel, is carried by the lower head. The spindle K carries the pulley 



Fig. 28. The Hoffmann Ball Grinding Machine—U. S. Patent No. 803,164 


Q which is driven by a belt running over idlers to the countershaft 
above. Head L is raised and lowered by the screw V and the bevel 
gears W. The indicator X, having a pointer as shown, is connected to 
this mechanism, and shows the operator how many thousandths inch 
more he must remove from the balls. With the introduction of this 
machine the cost of making balls was cut in two, and the quality 
obtained was far superior to anything which had so far been produced. 









































































30 


No. 116—MANUFACTURE OF STEEL BALLS 


The Hawthorne Method of Rough. Grinding 

About the time when the writer had designed the machine just 
described, the Hawthorne Mfg. Co., of Bangor, Me., decided to enter 
into the manufacture of steel balls. This company originally manu¬ 
factured boot calks and other lumbermen’s supplies. Some articles 
were manufactured for this concern by the Simonds Rolling Machine 
Co., and representatives of the company frequently visited the Simonds 
plant. They observed the great number of balls that were beginning 



Fig, 29. Improved Hoffmann Ball Grinding Machine—TJ. S. Patent No. 868,926 


to be used in this country, and hence concluded to enter into this field. 
The first grinder employed by this company made use of sand instead 
of emery. A bed of sand had been found in which the grit was so 
hard that it would cut the surface of a ball and last for a considerable 
length of time before being pulverized. The grinding was done in a 
closed path in which water and sand were used freely. The sand was 
fed from bins overhead, and washed out by water when pulverized. 










































































































































































GRINDING AND HARDENING 


31 


This was a very cheap process, as far as the grinding material was 
concerned, but did not produce a perfectly spherical blank. The oil 
or finishing grinders had to be relied upon to round up the balls, and 
a great many seconds and thirds were produced. The process was 
applicable, however, to the small balls mostly used at that time, nearly 
all balls being employed in bicycles. For larger balls, such as are 
now used in automobiles and other machines of the present day, these 
machines would have been useless. 


The Putnam Ball Grinding- Machine 

About 1899, Mr. H. M. Putnam, who for several years was connected 
with the Simonds Rolling Machine Co., started the Fitchburg Steel 
Ball Co., and invented a dry grinder, as shown in Figs. 25, 26 and 27. 
This machine, which had to be constructed without the Richardson path, 
was made in the following manner: The lower plate A which corre¬ 
sponds to the drive ring, was driven through the tube B which carries 
the pulley C. The plate D which is countersunk as indicated at E, 



Fig. 30. Section of Ball Heating- Furnace, made by the American 

Gas Furnace Co. 


Fig. 27, (see also Fig. 25) is made from saw steel and hardened; it is 
then forced onto spindle F which carries pulley G. The cylinder H is 
adjustable by means of the screw thread K, and can thus, by means 
of handwheel 0, be raised or lowered by the operator so that the balls 
will come in contact with the emery wheel L. This wheel is fastened 
to the upper spindle N, which is driven from pulley M by a belt passing 
over two idler pulleys to the countershaft on the floor, as shown. This 
machine is very simple, but it does not grind an accurate ball on 
account of the balls being at various distances from the center, thereby 
giving them different rates of speed. The outer balls are ground faster 
than those at the center, and thus balls of all kinds of diameters and 
degrees of accuracy are produced. The balls are not held firmly in the 
r^th as in the Richardson grinder, but are simply confined in the 



































32 


No. 116—MANUFACTURE OF STEEL BALLS 


countersunk holes so that they will not be thrown from the plate. This 
allows the ball to take its own course, and it becomes badly out of 
round during the grinding process. The writer is of the opinion that 
this machine might have been improved, but the company discontinued 
business soon after the machine was built. 

The Chicago Steel Ball Co.’s Grinder 

About the same time the Chicago Steel Ball Co., of Chicago, Ill., 
brought out a dry grinder which had several good features, and which 
was somewhat similar in operation to the well-known Hoffmann machine 
which will be described in detail in the following. The Chicago Steel 
Ball Co.’s machine had the emery wheel and the drive wheel placed in 
a vertical position. There were several concentric circular paths on 
the drive ring, and the balls were transferred from one into another. 



thus giving the balls a different spiral motion on account of being at 
various distances from the center. This machine ground a very ac¬ 
curate ball, but on account of its poor construction and the poor method 
used for transferring the balls from one path to another, it was but 
little used, and, therefore, had no particular influence on ball manu¬ 
facturing methods. 

The Hoffmann Grinder 

What may be considered as one of the best ball grinding machines 
constructed was invented in 1905 by Mr. E. G. Hoffmann, who was at 
that time connected with the Hoffmann Ball Co., in England. This 
machine required several years for its development, but when com¬ 
pleted it produced a very accurate ball, and is greatly appreciated by 
ball manufacturers. 

In the preceding chapter, the Hoffmann ball turning machine was 

























































GRINDING AND HARDENING 


33 


described. The blanks produced by this machine are accurate, and 
but little grinding is required on them. These balls, therefore, are 
especially suited for grinding in the Hoffmann grinder, as this machine 
is very slow, and cannot be used to advantage on pressed blanks or 
forgings, unless they have been previously rough ground by some other 
process. The machine is automatic, and requires little or no attention, 
except for gaging the balls at intervals during the grinding. The 



■ 


'i 


Fig. 32. General View of the Grant Dry Grinding Machine, with 
Samples of Largest and Smallest Balls ground in it 

machine requires from three to five hours for removing 0.001 inch on 
a %-inch ball. 

In Fig. 28, diagrammatical illustrations of the Hoffmann machine 
as originally designed, are shown. Pulley D is driven by a belt from 
the countershaft, and revolves upon a stationary shaft B. The pulley 
is fastened to the disk C which has a series of grooves in its face. 
Plate A, which also has a series of concentric grooves to correspond 
with those on disk (7, is stationary and is fastened to shaft B. The 
balls are placed in the machine so as to fill all the concentric grooves, 
spring E forcing disk C against plate A, thus holding the balls in place. 
The machine is then started, and the balls, by means of the mixer and 












34 


No. 116—MANUFACTURE OF STEEL BALLS 


interchanger shown in two views at H and K, are changed from one 
groove to another. 

As indicated at K and L, slots F are cut through the stationary 
disk, a slot being directly opposite each of the grooves M. In each slot 
is placed a finger N which projects slightly beyond the bottom of the 
groove into the corresponding groove in the rotating disk G. The 
function of the finger is to stand in the path of the balls so as to 
positively dislodge each ball from the groove as it reaches the point 
where the finger is located. Each finger discharges the ball from the 



Fig-. 33. Special Grinding Machine used for Grinding the Segments for 
the Path of the Balls in the Machine shown in Fig. 32 


corresponding groove upon a table G which affords a surface upon 
which the balls may roll, and which also directs the balls back toward 
the grooves below the fingers, the table being slightly inclined toward 
the lower portion of the slots F. It will be seen that this keeps the 
balls moving from one groove to another so as to place them at differ¬ 
ent distances from the center at each revolution of plate A. This 
results in the grinding of a very accurate ball. 

The grinding is done with oil and emery introduced in the required 
quantities upon the table G, and fed into the machine by the balls. 
This machine was further improved by the introduction of an emery 
wheel in place of the grinding ring C. The improvement was very 
marked, as the grinder C , when made of cast iron, was apt to be spongy, 









GRINDING AND HARDENING 


35 



and softer in some spots than in others; it would, therefore, quickly 
wear out of shape. The replacing of this disk by the emery wheel 
overcame these difficulties. Kerosene oil is used to keep the grooves 
clear of the loose particles of abrasive material, and prevents the balls 
from being badly scratched or cut. A very peculiar fact about this 
grinder is that the emery wheel is run at only 75 revolutions per 
minute, instead of at the peripheral speed of 5000 feet, generally re¬ 
quired by emery wheel manufacturers. 

Annealing- and Hardening 

After the balls have been rough ground so as to remove all scale and 
decarbonized surface resulting from the forging operation, they are 


Fig. 34. The Oil Grinders 

taken to the hardening room where they are first annealed. This 
annealing removes any internal stresses caused by forging or other 
methods of blanking. The process, as indicated in Fig. 30, is auto¬ 
matic. The balls are fed into the hopper B which is revolved by a 
worm and worm-wheel placed at the opposite end of the machine. 
From this hopper the balls are fed into the spiral E which they follow 
until they reach the opposite end, where they drop into the outer spiral 
H, which is revolved in the opposite direction. Finally the balls fall 
out of the cylinder at I into the funnel K. The machine is heated by 
gas with burners at R, thus preventing the heat from coming into 
direct contact with the balls and decarbonizing the surface. 











36 


No. 116—MANUFACTURE OF STEEL BALLS 


After being annealed, the balls are put through the same machine 
to be heated for the hardening. They are heated to exactly 1275 
degrees F., the temperature being determined by a pyrometer. The 
thermo-couple is placed near the point where the balls leave the 
cylinder. 

The smaller balls are dropped into a reservoir of oil, while the larger 
ones are immersed in brine. The oil reservoir, shown at A in Fig. 31, 
consists of a length of 30-inch water pipe, one end being provided with 
a head strongly bolted to it so that it is water-tight. The pipe is sunk 
into the ground so that the top can receive the balls, as indicated at L, 
Fig. 30. Inside of this cast-iron pipe is placed a coil of 1% inch water 
pipe, in which cold water is circulated in order to keep the bath cool. 
A rod with a number of inverted galvanized iron cones B, adjustably 
fastened onto the rod by the holders C, is then placed in the bath. 
(Parts B and C are also shown in detail in Fig. 31.) When the balls 

drop into the bath in the pipe, they 
strike the side of the upper cone, 
which shoots them off at an angle 
until they strike the opposite side of 
the next cone; this reverses their di¬ 
rection of motion, so that they reach 
the basket at the bottom in a zig¬ 
zag path, thoroughly cooled off. 
When the balls are thus cooled off, 
the rod with the basket at the lower 
end is pulled out, and the balls in 
the basket are allowed to drain, the 
oil draining back into the pipe. 

The best oil for the hardening of 
balls is cotton-seed oil; while it is 
very expensive, it has sufficient body 
to cool the balls thoroughly, and it 
does not need to be replaced. It is only necessary to add to it, from 
time to time, due to the loss from evaporation. 

The larger balls are hardened in brine. The machine shown in Fig. 
30 is placed at the edge of a tank of the type shown at D, Fig. 31. This 
tank has a series of shutters made in the from of steps overlapping 
each other as indicated. These steps force the balls to traverse in a 
zigzag path through the brine in the tank for a considerable time 
before dropping into the basket at the bottom. 

The largest balls are heated for hardening by being placed on the 
tiling of a regular casehardening furnace, similar to that made by the 
Brown & Sharpe Mfg. Co., and are allowed to heat slowly through to 
the center, the balls being revolved gradually. Two or more balls, 
according to size, are then placed in a wire basket and rapidly swung 
to and fro in the brine tank until thoroughly cooled off. All balls, as 
soon as they are taken from the hardening tanks are placed in a kettle 
of boiling soda, not only for the purpose of washing them, but also to 



Fig. 35. Illustration of Principle of 
Action cf Oil Grinders 





















GRINDING AND HARDENING 


37 


prevent the air from coming in contact with them at a time when they 
are extremely hard. The balls are then placed in the drawing kettles, 
which are filled with oil heated to 325 degrees F. 

Finish Grinding 

The balls are now ready to return to the finish dry grinding depart¬ 
ment, where the same machine as shown in Fig. 24 is used (except 
that a finer grade of emery wheel is employed) to reduce the balls to 
the proper size for the oil grinders. For this finish dry grinding the 
inner and outer segment are ground true, so that the path formed is 
a perfect track for the balls. 

In Fig. 32, the improved Grant machine (Fig. 24) is shown, with the 
two extremes in size of balls which this machine will grind. In Fig. 
33 is shown the special grinding machine which is used for grinding 
the segments that form the path for the balls. These special grinders 
are very simple in construction, the wheel head being solid and the 
spindle on which the segment plate is fastened being driven by a worm 
through a shaft from a pulley in the rear. The two adjustments up 
and down and in and out are operated by the shafts which project in 
the front. By this grinding, the segments are made absolutely true, 
and by grinding the drive ring by the emery wheel on the machine on 
which it is used, the balls will make contact on three points absolutely 
true' with each other, and hence the balls produced will be absolute 
spheres, ready for the final oil grinding. 

Fig. 34 shows the ordinary type of oil grinders. These are usually 
placed in groups of three. The machines are provided with a quill, on 
which a rack is cut for raising and lowering the head by means of the 
lever shown projecting at the front of the machine. The machines 
run about 450 revolutions per minute. The oil grinding constitutes 
the final finishing operation, and requires considerable skill. The 
operator must know just how much oil and emery to use, and how 
long to run the rings so as to make the balls round up. 

Assume, for example, that a man is to finish grind balls % inch in 
size. In Fig. 35 is shown a diagrammatical section of the grinding 
rings. The circular path of the balls is usually 16 inches in diameter. 
A half circular groove is cut in the bottom ring, as indicated, and a 
small channel is cut at the bottom of the groove to allow the oil and 
emery to reach the bottom of the ball. The top ring is simply a cylinder 
shrunk onto a plate. This plate can be used over and over again, by 
merely breaking off the cylinder when used up and shrinking a new 
ring in place. The upper cylinder has a shallow groove in it for the 
balls. After the balls have been placed in the ring, the oil and emery 
are poured in, and the upper ring is lowered onto the balls, the machine 
then being ready to start. The i/i-inch balls should have 0.006 inch 
left for the finishing operation. The operator gages the balls and sets 
his clock on the head of the machine as many minutes ahead of the 
clock in the room as he knows will be required to obtain very nearly 
the final size. At this time he must stop the head and again measure 


38 


No. 116—MANUFACTURE OF STEEL BALLS 


the balls. The operator runs three heads, and as each head finishes 
its work at different intervals, he has ample time to stop any one head 
and take out three or four balls from different parts of the ring. After 
washing them in benzine, he measures them with his micrometer, 
testing both the size and roundness; if not to size, he replaces them 
and applies the required amount of oil, emery and speed, until he 



Fig. 36. Ring Turning Lathe for Dressing the Oil Grinder Rings 


obtains a ball that is as nearly perfect as possible in all respects. 

The grinding ring should be of porous medium soft cast iron, as the 
oil grinding is merely a lapping process, and the ring must wear away 
to allow the balls to round up. On account of the larger diameter at 
the outside Y than at the inside X of the balls, Fig. 35, there is a 
greater peripheral speed at the outside. This causes the balls to move 
in a spiral path, as they revolve, so as to bring all points of the surface 
in contact with the ring. The operator, when using a new ring for 
the first time, must make allowance for the ring not having become 
penetrated with emery, and also for its being cold. Later the output 
can be greatly increased. The heads on the grinders must be kept 
in perfect alignment, so that the balls will be ground on the entire 
circumference of the rings. 

Fig. 36 shows a special ring turning lathe for dressing the oil grinder 
rings. It is necessary that these rings be free from chatter marks 
and imperfections of any kind, so that even the first sets of balls ground 
by them will be perfect; otherwise the first balls would have to be 
classified as seconds or thirds on account of poor grinding. 














CHAPTER III 


INSPECTING, GAGING AND TESTING OF BALLS 

In the present chapter, the inspection, grading, gaging, and testing 
of the balls are described, and a few points given for the benefit of the 
user and purchaser of steel balls. 

The Burnishing- and Tumbling- Processes 

When the balls come from the oil grinders, they have a dull finish 
and must be burnished or tumbled. The burnishing can be done in 
the oil grinder with a set of rings having grooves in them the exact 
size of the balls. A light oil is used, and after a very short run of the 
machines, a finely polished surface will be produced. This process, 
however, is expensive, and the ordinary tumbling method is most gen¬ 
erally used. The tumbling barrel universally adopted is of the regular 
iron tilting type. The balls are placed in the barrel in sufficient 
quantities so that, when they roll over and over, their weight will 
cause enough friction between them to polish them. A polishing ma¬ 
terial is placed in the barrel, and the latter is allowed to run at least 
ten hours to produce a good surface. The balls are then cleaned off 
by tumbling them in sawdust, and later placed in another barrel with 
finely cut kid leather. This final tumbling brings out the high polish. 

Inspection 

The balls are now ready to be inspected, which is done almost exclu¬ 
sively by girls. The skill and rapidity which can be obtained in doing 
this work is certainly most remarkable. One girl can inspect fifty 
thousand ^4-inch balls in ten hours. This inspection is done on glass 
plates which are about ten inches square and inserted in a frame so 
that the balls cannot roll off. The under side of the glass is painted 
so as to reflect the light. The plate is about half filled with balls and 
is placed upon a box which is titled slightly towards the inspector. 
This causes the balls to always roll to the front. The inspector holds 
in her hand a magnet resembling in shape a knitting needle. The end 
is sufficiently magnetized to raise one ball of the size being inspected 
from the glass. In the other hand the inspector holds a piece of heavy 
white paper 4 inches wide by 8 inches long, which sheet slides under 
the balls. This makes the balls revolve, and with the magnet defective 
balls are picked out. The defects consist of pits, bands, dents, scale, 
rough grinding marks, etc. 

The different grades are separated in boxes, placed to the right of 
the inspector, and they are used for different purposes according to 
the requirements placed on the balls. It is evident that different 
grades of balls may be used when it is remembered that ball bearings 
are employed in so many different kinds of devices, such as bicycles, 
clothes-wringers, hand trucks, sash pulleys, etc. 


40 


No. 116—MANUFACTURE OF STEEL BALLS 


After the balls have been inspected for defects they are rolled back 
and forth on the glass plate in order that those that are out of round 
may be picked out. As the balls which are not perfectly spherical will 
take a zigzag motion when rolling down the plate, and the true balls 
will run straight, it is comparatively easy for the inspector to pick 
out the imperfect ones. An expert inspector does not stop each time 
she picks up a ball to place it in the boxes, but will usually toss it into 
the palm of her hand, which will generally hold all of one grade that 
she will pick out from the batch of balls on the plate. Balls larger 
than % inch in diameter are generally taken up by hand and looked 
over. Those that are out of round in the larger sizes are taken out 
while measuring the balls. 


Grades of Balls 

Balls are generally graded into four main classes, known as alloy, 
and A, B, and C grades. The steel for the alloy balls contains chro¬ 
mium, and these balls have the greatest crushing strength. They 
must be absolutely free from defects as regards material and finish, 
and must not vary in size more than 0.0001 inch. Balls classified as 
A-grade are made from high-grade tool steels, accurately finished, and 
thoroughly inspected, and must not vary over 0.001 inch above or below 
the exact dimension. The balls known as B-grade are the seconds 
taken from the two higher grades mentioned. These are the balls 
which show slight, almost invisible, defects, and which vary from 
0.001 to 0.002 inch. The C-grade, commonly known as hardware balls, 
are those picked from the higher grades when these show a defective 
surface. Whether these balls are gaged or not depends upon the use 
to which they are to be put. 

The Gaging- of the Balls 

After the inspection, the balls are automatically gaged, the gaging 
being done in a gaging machine in which the balls are fed from a 
hopper and allowed to roll down between two hardened straightedges 
and to fall into tubes which carry them to the proper drawer, as indi¬ 
cated in Fig. 37. This illustration shows the Grant ball measuring 
machine. At A is shown the automatic dropping machine, and at B 
the delivery spout through which the balls drop into the measuring 
slides C, provided with a longitudinal slot or opening O between them. 
The sides of the slot may be accurately separated any desired amount 
by the micrometer adjusting screws provided at both ends. Conse¬ 
quently, the flare of the slot may be adjusted so that it is possible to 
determine exactly what the diameter is of the balls that will drop into 
each of the tubes and drawers beneath the measuring slide as the balls 
roll down along it. 

As is clearly shown in the illustration, pockets are arranged succes¬ 
sively beneath the inclined slot, and are connected by pipes with the 
drawers of the cabinet underneath. It is evident that in this way balls 
of the same size will go into the same drawer each time, the balls 
that go into the middle drawer being those of correct size, those that 


INSPECTING, GAGING AND TESTING 


41 



go into the upper drawers being those that are too small, while the 
large balls will go into the lower drawers. The balls that are entirely 
too large will run down the full length of the measuring slide and 
will be deposited in the box X. Those that are deposited in the drawers 
of the cabinet will be from 0.0025 to 0.005 inch too large or too small, 
according to the setting of the slides. 

The exact arrangement of these measuring devices varies somewhat. 
In Fig. 38 is shown a group of the type of machines just described. 
A rack is run through the center of the machine. In this rack, directly 
under the hopper, there is a hole having a bushing in it of the size 
of the ball to be gaged. The ball drops from the hopper into this bush¬ 
ing and is carried forward until it comes to an opening which is con- 





















































































































































42 


No. 116—MANUFACTURE OF STEEL BALLS 


nected with a tube for carrying the ball to the measuring slides. The 
rack is operated by a sector of a gear mounted on a shaft having an 
eccentric pin on one end and a pulley on the other. Inside of the 
hopper there is a small tube which is operated up and down by two 
levers, one being attached to the eccentric pin and the other to the 
tube. This arrangement prevents the balls from clogging so that the 
bushing in the rack is always ready with a ball to carry forward, 
thereby constantly feeding balls to the measuring slides. 

In Fig. 39 is shown a Grant machine with the measuring slides 
removed. This particular machine is worked by a worm and worm- 
wheel instead of by a rack. There are two disks, beneath the balls 
in the hopper, the upper one of which is keyed to the shaft fastened ?o 
the worm-wheel and hence revolves. This disk has a series of holes 



drilled near the periphery, these holes being 0.005 inch larger than the 
ball to be gaged. The lower plate has a hole in it directly above the 
measuring slide, so that when the upper disk carrying the balls pre¬ 
sents a hole directly above the hole in the lower disk, the ball will 
drop through the hole and tube into the measuring slide. As the 
hopper is full of balls there is a liability of clogging, because two balls 
may have a tendency to drop through the hole at once when the open¬ 
ing is presented. The clogging tendency is overcome by a cut-off made 
of a thin piece of tool steel with beveled edges, which covers two holes 
in the revolving disk, the holes covered being the one directly over the 
lower disk and the one next to follow. This prevents jamming of the 
balls. The remainer of the machine and cabinet is substantially the 
same as in the machine shown in Fig. 37. 

In the Putnam gaging machine the hopper is worked practically the 













INSPECTING, GAGING AND TESTING 


43 


same as in a machine for slotting screws. Fingers raise the ball, 
allowing it to fall into a trough, and then through a tube onto the 
measuring slides. 

This mechanical gaging and sorting of balls is applied to all sizes 
up to and including % inch. The large sizes are measured by hand 
by micrometers. The girls employed for this work pick them up one 
by one and measure each ball separately over several diameters, throw- 



Fig. 39. A Modified Type of Grant Measuring Machine, with Gaging 

Slides removed 


ing them into small boxes placed before them, each of the boxes con¬ 
taining a certain size of balls between the limits of measurements 
adopted. This work is very rapidly done, as the operators become 
very skillful. 

Counting” the Balls 

The next operation is the counting and boxing of the balls which at 
first sight might be assumed to be a tedious and very slow operation. 
So it would be were it not for the mechanical means adopted for doing 
this work. Balls up to % inch in diameter are counted by means of a 
counting board, as indicated in Fig. 40, which has holes sunk in it 
0.010 inch larger than the ball. Around the board is tacked a narrow 
strip of wood to prevent the balls from rolling off. The balls are then 
poured upon the board and all balls which do not find a hole to enter 
are allowed to run off. As there is a predetermined number of holes 
In the board, the counter immediately knows how many balls she has, 
and she transfers them immediately from the counting board into a 


















44 


No. 116—MANUFACTURE OF STEEL BALLS 


pasteboard box in which the balls are packed. In this way one girl 
can easily count a million balls a day and do other work besides. 

The pasteboard boxes are made of a telescoping form, lined with 
paper which is free from acid and which has previously been soaked 
in an anti-rust compound. The balls, which have a very high polish, 
would otherwise easily rust on account of sweating, which is caused 
by the difference in temperature of extreme heat and cold. It is very 
essential that steel balls should be kept in a room properly heated. 

The Testing- of Balls 

The testing of a steel ball for crushing strength should be done 
between hardened plates by placing three balls in a tube into which 
they nearly fit. The center ball is the one that will be tested. The 




M" 


lunar 




Machinery 


Fig-. 40. Counting Board for 5/16-inch Balls 

upper and lower balls will, of course, sink into the plates, and this will 
give them more of a surface bearing than the middle ball, which bears 
only in two points upon the upper and lower balls; hence the middle 
ball will ordinarily give way first. As the pressure is applied, a double 
pressure cone will be formed inside of the ball, this cone having its 
apexes where the outside balls bear on the middle ball. If properly 
hardened, a ball will break into several pieces. This method is the 
proper way to test a ball, but there seldom are two balls that will 
stand exactly the same load when tested. This is caused largely by 
the methods in which the ball blank is made. As will be remembered 
from the description of the making of the blanks in the first chapter 
of this book, the balls in the forging process are much more compact 
at what might be called the “poles,” that is, where they join the 
next ball forged, than at the “equator.” Therefore, if the center ball 

























INSPECTING, GAGING AND TESTING 


45 


being tested has the point of contact on the “equator,” it will not 
stand within ten or twenty per cent of the load that it would stand 
if the points of contact were at the “poles.” The same method of 
reasoning may be applied to stamped and turned balls. 

Through the means of this testing operation and the appearance of 
the fracture, it can be determined whether the balls have been properly 
hardened. Every batch of steel, no matter how carefully made, usually 
requires a slightly different treatment in hardening, and what this 
treatment is must be determined by the man responsible for the hard¬ 
ening work. The accompanying table shows the crushing load ordin¬ 
arily required by ball manufacturers for regular tool-steel balls. 


Size of 

Ultimate Strength 

Size of 

Ultimate Strength 

Ball 

of Ball 

Ball 

of Ball 

in Inches 

in Pounds 

in Inches 

in Pounds 

1/16 

390 

5/8 

39,000 

3/32 

875 

3/4 

56,250 

7/64 

1,562 

13/16 

66,000 

1/8 

2,450 

7/8 

76,000 

3/16 

3,496 

15/16 

88,000 

7/32 

4,780 

1 

100,000 

1/4 

6,215 

1 1/8 

125,000 

5/16 

9,940 

1 1/4 

156,000 

3/8 

14,000 

1 1/2 

225,000 

7/16 

19,100 

1 5/8 

263,000 

1/2 

25,000 

1 3/4 

306,000 

9/16 

31,500 

2 

400,000 


The figures above have been adopted after a great many years of test¬ 
ing and are considered by the manufacturers safe figures with which to 
calculate. Of course, in selecting a ball for a bearing, a factor of safety 
of ten should always be adopted unless the bearing is used in an ex¬ 
tremely narrow space. The grooves in which the balls run when heavy 
loads are imposed should be round and not of V-form. No figures can 
be given relating to tests of balls made from alloy steel, because these 
steels give such irregular results that the manufacturers have been 
unable to compile any data that would be in any way satisfactory. It 
is, however, safe to state that the alloy-steel balls will stand from 25 to 
50 per cent more than the regular tool-steel balls. 


Balls of Other Materials than Steel 

Balls are made of a great many other materials, brass and bronze, 
for instance, being used extensively for oil-well devices where acid is 
found in the crude oil. Such balls are also used in valves where the 
material to be pumped will rust steel balls and cause corrosion, and 
also in electrical work. German silver balls are used in Yale locks to 
prevent corrosion when used on shipboard or in other places where they 
would be subjected to the damp sea air. Casehardened machine steel 
balls are used extensively in agricultural implements and similar ap¬ 
paratus on account of being inexpensive. Chilled cast-iron balls are 
used in turntables, trucks, and for similar requirements. 



46 No. 116—MANUFACTURE OF STEEL BALLS 

Points for the User and Purchaser of Steel Balls 

In the following the essential points relating to the manufacture of 
balls which should be kept in mind by a purchasing agent or consumer 
are given. Nothing but a tool-steel ball should be used for high-grade 
work, and it is very important that it be properly heat-treated. Do not 
be deceived by a finely polished ball, as high polish and deep scratches 
(which show only under a magnifying glass) do not necessarily indi¬ 
cate a good ball. In fact, the outside appearance has little or nothing to 
do with the wear of a ball, for a dull looking ball may be just as good 
as one with the highest polish. The polish is merely the result of the 
tumbling process. 

The first requirement is that the right material has gone into the 
balls. It costs but little to have the steel analyzed so that the purchaser 
may know whether he is getting a tool-steel ball or a machine-steel ball. 
The fact that the ball has only a point bearing makes it the more im¬ 
portant that it be made from good material in order to stand the pres¬ 
sure to which it may be subjected. Casehardened machine-steel balls 
ought not to be used when heavy duty is required. Naturally there is 
some difference in the quality of the steel that costs thirty-five dollars 
per ton from that which costs one-hundred-fifty dollars per ton. 

It is true that a ball can be casehardened very deeply, in fact, almost 
through to the center, but it should be remembered that casehardening 
implies adding carbon to the steel under a high heat, which causes the 
pores in the steel to open so that the carbon can enter. The process, 
however, does not remove the injurious elements, such as phosphorus, 
sulphur and silicon, of which the cheaper steel contains a large percent¬ 
age. It is, of course, perfectly satisfactory to use casehardened balls 
for many purposes, but when it comes to a really high-grade article, the 
highest class of steel is to be preferred. 

In order to determine whether a ball has been properly heat-treated, 
place the finished ball in a piece of waste on an anvil and break it open 
with a heavy blow. The waste prevents the pieces from flying around. 
If the ball is properly heat-treated, the break will show a soft silky-ap¬ 
pearing surface—the grain of the steel being fine. If it has not been 
heat-treated, it will look coarse and granular, having more the appear¬ 
ance of cast iron. 

If during the test the ball should break in half, it Would indicate 
that it had not been properly drawn after hardening, but was still 
subjected to internal stresses. If such a ball is placed in a bearing, 
it will easily break if subjected to a severe shock or strain. If a 
ball has been properly drawn it can be touched with a fine Swiss file, 
and under the blows of a heavy hammer it will dent slightly and break 
into several pieces. 

Balls over 5/16 inch in diameter that have been turned or headed 
should not be used for heavy duty, as they are not as good as balls for 
which the blanks have been forged. The headed ball, on account of the 
severe shock to which the metal is subjected when cold, cannot be 
treated so as to stand the strain that the forged ball will stand. A 


INSPECTING, GAGING AND TESTING 


47 


turned ball is cut from a rod which is rolled, so that the grain of the 
steel is in a lengthwise direction; hence when a ball is turned from 
this bar the surface of the ball consists of a mass of exposed fibers. 
When put under a heavy strain, as in a thrust bearing, it will pit and 
flake off. The surface of the ball should be smooth, that is, all the 
marks from the rough-grinding process should have been removed in 
the finish-grinding. If this has been done it can be readily determined 
by a magnifying glass. 

A ball made from a forged blank cannot be hardened properly unless 
the decarbonized surface has been wholly removed. Some manufac¬ 
turers attempt to keep the forgings as small as possible in order to 
save material and time in grinding, and in many cases it is then im¬ 
possible to remove all of the decarbonized surface. Hence when the 
ball is hardened, rough marks and soft spots can be detected. The 
soft spots are much brighter than the properly hardened surface. 

If balls are to be used for special purposes, this should be designated 
in the order sent to the ball manufacturer. In order to be able to 
supply a ball that will give satisfaction, it is necessary that he be 
furnished with information as to what the ball is to be used for, the 
speed and load at which it will be used, and the kind of bearing em¬ 
ployed. Then the balls can be drawn to a degree of temper adapted 
to the particular purpose in view, and thus satisfaction can be guar¬ 
anteed to the purchaser. It is also very important to see that the 
balls that are furnished are not out of round, as this would cause the 
bearings to “catch” and “jump.” The resulting bearing will run unsat¬ 
isfactorily, and will rattle on account of the fact that the balls are 
loose at one point and tight at another. The actual size of the ball 
does not make a great deal of difference, provided the balls are all of 
the same size. In other words, in a lot of one-hundred-thousand balls, 
if they are found to be 0.0005 or 0.001 inch under size they will give 
satisfaction if they are all used before the next shipment can get mixed 
up with them. 

It has already been mentioned that the temperature of the room in 
which the balls are stored must not be too low. The temperature of 
the stock-room should be kept the same at all times, and on Sundays 
and holidays, when the factory is closed, it should be especially heated, 
for a ball which becomes very cold and then is brought back to a 
warm temperature will soon begin to rust and cause a great deal of 
trouble. 

Summary of Ball-making- Processes 

In order to fix in the reader’s mind the various processes that a 
ball passes through, from the time that the blank is produced from 
the rough stock until the finished ball enters the stock-room, a general 
summary of the processes described in the three chapters comprising 
the present treatise on the manufacture of steel balls will be given. 

There are several methods for producing the ball blank. One is that 
of turning the ball blanks in a special automatic machine. This method 
is rapid and makes it possible to produce a blank which requires less 


48 


No. 116—MANUFACTURE OF STEEL BALLS 


grinding than the blanks produced by other methods, but on account 
of the fact that the fibers of the stock from which the blank is turned 
are cut and exposed at the surface, a ball so made is of inferior strength 
after hardening as compared with balls the blanks of which are made 
by other methods. 

Another method commonly used for producing ball blanks is to 
form the blank in a heading machine. A bar is fed into the machine 
and pieces of the required length are cut off and headed between dies 
to a ball shape. This is a very rapid method, and balls up to, say, 
5/16 or % inch in diameter can be made advantageously by this process. 
As there is no waste, this process for smaller sizes of balls must be 
deemed the best as well as the cheapest of the methods used at the 
present time. 

The best method of making ball blanks from % inch to 2 inches in 
diameter is known as string forging. This method is very extensively 
used and the balls so produced, when properly heat-treated, are strong 
and tough in their structure. The balls which have been produced by 
the heading or forging process must have the fin or flash ground off 
before they pass to the grinding machines. The process by means of 
which the fin is removed is called “flashing,” and the machine in which 
it is done is ordinarily termed a “rotary” file. Large balls are flashed 
separately in a special fixture by an ordinary emery wheel. 

The balls are now ready for the dry-grinding process, the grinding 
being done by an emery wheel acting upon the balls which are held 
and rotated by suitable means. After being dry-ground, the balls are 
annealed and then hardened, the smaller balls being quenched in cotton¬ 
seed oil, while the larger ones are immersed in brine. After hardening, 
the balls are washed in boiling soda and then tempered in oil. 

After the tempering, the balls are ready to return to the finish dry¬ 
grinding department, and are finish dry-ground in machines of the 
kind that performed the rough dry-grinding, but a finer grade of emery 
wheel is used. From the finishing dry-grinders the balls pass to the 
oil grinders, where the final grinding operation is performed and where 
the balls are brought to exact size. The oil grinding operation is prac¬ 
tically a lapping process, no grinding wheel being used. The machine 
has merely two plates, one of which is grooved, between which the 
balls roll. The grinding medium is fine emery and oil. 

When the balls have been brought to size in the oil grinders, they 
are given their final finish either by burnishing them in machines 
similar to the oil grinders, or by being tumbled in a tumbling barrel 
with a polishing medium. Next they are tumbled in sawdust, and 
finally in a barrel with cut-up kid leather to obtain the high polish. 
The balls are then inspected, graded and gaged. The smaller balls are 
gaged in gaging machines, while the larger are measured by microm¬ 
eters. Next the balls are counted and packed into boxes and sent to 
the store-room, which finishes the operations. 


No. 67. Boilers. 

No. 68. Boiler Furnaces and Chimneys. 

No ; 69. Feed Water Appliances. 

No. 70. Steam Engines. 

No. 71. Steam Turbines. 

No. 72. Pumps, Condensers, Steam and Water 
Piping. 


LOCOMOTIVE DESIGN AND RAILWAY SHOP 
PRACTICE 

No. 27. Locomotive Design, Part I. 

No. 28. Locomotive Design, Part II. 

No. 29. Locomotive Design, Part III. 

No. 30. Locomotive Design, Part IV. 

No. 79. Locomotive Building. — Main and Side 
Rods. 

No. 80. Locomotive Building.—Wheels; Axles; 
Driving Boxes. 

No. 81. Locomotive Building. — Cylinders and 
Frames. 

No. 82. Locomotive Building.—Valve Motion. 

No. 83. Locomotive Building.—Boiler Shop Prac¬ 
tice. 

No. 84. Locomotive Building.—Erecting. 

No. 90. Railway Repair Shop Practice. 

ELECTRICITY—DYNAMOS AND MOTORS 


No. 34. Care and Repair of Dynamos and Motors. 
No. 73. Principles and Applications of Electricity. 

—Static Electricity; Electrical Measure¬ 
ments; Batteries. 

No. 74. Principles and Applications of Electricity. 

—Magnetism; Electric-Magnetism; Elec¬ 
tro-Plating. 

No. .75. Principles and Applications of Electricity. 

—Dynamos; Motors; Electric Railways. 
No. 76. Principles and Applications of Electricity. 

—Telegraph and Telephone. 

No. 77. Principles and Applications of Electricity. 
—Electric Lighting. 

No. 78. Principles and Applications of Electricity. 
—Transmission of Power. 

No 115. Electric Motor Drive for Machine Tools. 


HEATING AND VENTILATION 

No. 39. Fans, Ventilation and Heating. 

No. 66. Heating and Ventilation of Shops and 
Offices. 

IRON AND STEEL 
No. 36. Iron and Steel. 

No. 62. Hardness and Durability Testing of 
Metals. 

No. 117. High-speed and Carbon Tool Steel. 

No. 118. Alloy Steels. 

FORGING 

No. 44. Machine Blacksmithing. 

No. 45. Drop Forging. 

No. 61. Blacksmith Shop Practice. 

No. 113. Bolt, Nut and Rivet Forging. 

No. 114. Machine Forging. 

No. 119. Cold Heading. 

MECHANICAL DRAWING AND DRAFTING- 
ROOM PRACTICE 


No. 2. 
No. 8. 

No. 33. 

No. 85. 

No. 86. 
No. 87. 
No. 88. 


No. 108. 
No. 109. 


No. 35. 
No. 110. 


Drafting-Room Practice. 

Working Drawings and Drafting-Room 
Kinks. 

Systems and Practice of the Drafting- 
Room. 

Mechanical Drawing.—Geometrical Prob¬ 
lems. 

Mechanical Drawing.—Projection. 
Mechanical Drawing.—Machine Details. 
Mechanical Drawing.—Machine Details. 

DIE-CASTING 

Die-Casting Machines. 

Die-Casting, Dies and Methods. 

MISCELLANEOUS 

Tables and Formulas for Shop and Draft¬ 
ing-Room. 

Extrusion of Metals. 


MACHINERY’S DATA BOOKS 

Machinery’s Data Books include the material in the well-known series of Data 
Sheets published by Machinery during the past fifteen years. Of these Data Sheets, 
nearly 700 were published and 7,000,000 copies sold. Revised and greatly amplified, 
they are now presented in book form, kindred subjects grouped together. The price 
of each book is 25 cents (one shilling) delivered anywhere in the world. 


No. l. 
No. 2. 
No. 3. 
No. 4. 

No. 5. 
No. 6. 
No. 7. 
No. 8 

No. 9. 
No. 10. 


LIST OF MACHINERY’S DATA BOOKS 


Screw Threads. 

Screws, Bolts and Nuts. 

Taps and Dies. 

Reamers, Sockets, Drills and Milling Cut¬ 
ters. 

Spur Gearing. 

Bevel, Spiral and Worm Gearing. 
Shafting, Keys and Keyways. 

Bearings, Couplings, Clutches, Crane 
Chain and Hooks. 

Springs, Slides and Machine Details. 
Motor Drive, Speeds and Feeds, Change 
Gearing, and Boring Bars. 


No. 11. 

No. 12. 
No. 13. 
No. 14. 
No. 15. 
No. 16. 
No. J7. 
No. 18. 
No. 19. 
No. 20. 


Milling Machine Indexing, Clamping De¬ 
vices and Planer Jacks. 

Pipe and Pipe Fittings. 

Boilers and Chimneys. 

Locomotive and Railway Data. 

Steam and Gas Engines. 

Mathematical Tables. 

Mechanics and Strength of Materials. 
Beam Formulas and Structural Design. 
Belt, Rope and Chain Drives. 

Wiring Diagrams, Heating and Ventila¬ 
tion and Miscellaneous Tables. 



library of concress 



A C H 0 003 130 j™"™ 

HANDBOOK 


For MACHINE SHOP 
AND DRAFTING-ROOM 


A REFERENCE BOOK ON MACHINE 
DESIGN AND SHOP PRACTICE FOR 
THE MECHANICAL ENGINEER, 
DRAFTSMAN, TOOLMAKER AND 
MACHINIST. 


Machinery’s Handbook comprises nearly 1400 pages of carefully edited and 
condensed data relating to the theory and practice of the machine-building 
industries. It is the first and only complete handbook devoted exclusively to 
the metal-working field, and contains in compact and condensed form the 
information and data collected by Machinery during the past twenty years. 
It is the one essential book in a library of mechanical literature, because it 
contains all that is of importance in the text-books and treatises on mechanical 
engineering practice. Price $5.00. 

GENERAL CONTENTS 

Mathematical tables—Principal methods and formulas in arithmetic and algebra— 
Logarithms and logarithmic tables—Areas and volumes—Solution of triangles and 
trigonometrical tables—Geometrical propositions and problems—Mechanics—Strength of 
materials—Riveting and riveted joints—Strength and properties of steel wire—Strength 
and properties of wire rope—Formulas and tables for spring design—Torsional strength 
—Shafting—Friction—Plain, roller and ball bearings—Keys and key ways—Clutches and 
couplings—Friction brakes—Cams, cam design and cam milling—Spur gearing—Bevel 
gearing—Spiral gearing—Herringbone gearing—Worm gearing—Epicyclic gearing—Belting 
and rope drives—Transmission chain and chain drives—Crane chain—Dimensions of small 
machine details—Speeds and feeds of machine tools—Shrinkage and force fit allowances— 
Measuring tools and gaging methods—Change gears for spiral milling—Milling machine 
indexing—Jigs and fixtures—Grinding and grinding wheels—Screw thread systems and 
thread gages—Taps and threading dies—Milling cutters—Reamers, counterbores and 
twist drills—Heat-treatment of steel—Hardening, casehardening, annealing—Testing the 
hardness of metals—Foundry and pattern shop information—The welding of metals— 
Autogenous welding—Thermit welding—Machine welding—Blacksmith shop information 
—Die casting—Extrusion process—Soldering and brazing—Etching and etching fluids— 
Coloring metals—Machinery foundations—Application of motors to machine tools—Dynamo 
and motor troubles—Weights and measures—Metric system—Conversion tables—Specific 
gravity—Weights of materials—Heat—Pneumatics—Water pressure and flow of water— 
Pipes and piping—Lutes and cements—Patents. 


Machinery, the leading journal in the machine-building field, the originator 
of the 25-cent Reference and Data Books. Published monthly. Subscription, 
$2.00 yearly. Foreign subscription, $3.00. 

THE INDUSTRIAL PRESS, Publishers of MACHINERY 
140-148 LAFAYETTE STREET 


NEW YORK CITY, U. S. A. 




























